Various designs of percutaneous needle guides for attachment to non-invasive medical scanning devices, for example, hand-held ultrasound transducer probes, are known in the art. These guides may be used to direct a percutaneous needle, for example, a biopsy needle, to a needle entry site, which is located alongside the scanning device on an epidermis of a scanned body, and which corresponds to a subcutaneous target located by the device. In order to direct the needle, these guides include a constraining feature through which the needle must be passed. Many of these guides further include means to adjust an angular orientation of the constraining feature, according to a measured depth of the located target, so that the needle inserted therein is directed to the insertion site at an angle that allows the inserted needle to intersect with the subcutaneous target.
Guides which only provide for an angular adjustment of the constraining feature, in order to re-direct the trajectory of the inserted needle, do not take into account situations when a particular angular orientation of the inserted needle is important for the needle to pass through the located target and gain access to a site beyond the target. Furthermore, handling of a guide including the aforementioned constraining feature, in conjunction with a proper handling of the scanning device and the needle, can increase a number of steps that a physician or clinician must take in order to gain percutaneous access to the target or the site beyond the target. Additionally, the constraining feature through which the needle must be passed in order to be guided by these guides can impose unnecessary limitations on a physician or clinician who has developed skills for “free-hand” handling of needles.